In isolated canine right atria, cells near the core of functional reentry had significantly reduced transmembrane potential amplitude, duration, and (dV/dt)max compared to cells in the periphery (P<0.001).
During functional reentry in isolated canine right atria, cells near the core have reduced transmembrane potential amplitude, duration, and upstroke velocity, supporting the spiral wave concept of functional reentry.
Absolute Event Rate: 58% vs 70%
p-value: p=<0.001
BACKGROUND: The characteristics of transmembrane potential (TMP) at the core of functional reentry in the atrium are not well understood. METHODS AND RESULTS: In protocol 1 (11 dogs), isolated perfused canine right atria were mapped from the endocardial surface while simultaneous TMPs were recorded from the epicardial surface. Episodes of reentry (n=64) were induced in the presence of 1 to 5 micromol/L acetylcholine. Successful simultaneous TMP recordings and activation maps were made in 8 episodes. The TMP was "near the core" if it was within 3.2 mm of the core; otherwise, it was considered to be "in the periphery." The mean cycle length of reentry was 110+/-35 ms. The TMP amplitude, duration (90% repolarization), and (dV/dt)max near the core (n=106) were 58+/-22 mV, 46+/-14 ms, and 33+/-20 V/s, respectively, significantly less than those in the periphery (n=241): 70+/-8 mV, 94+/-32 ms, and 55+/-10 V/s (P<0.001 for all). In 2 episodes of reentry, the cell at the core remained unexcited at its resting membrane potential. In protocol 2 (2 dogs), we performed simultaneous high-density mapping in 4 episodes of reentry and showed synchronous activation patterns on both surfaces with similar locations of the core. CONCLUSIONS: During meandering functional reentry in isolated canine right atria, (1) TMPs of cells near the core have a reduced amplitude, duration, and (dV/dt)max, and (2) cells at the core may remain unexcited at their resting membrane potential. These findings are compatible with the spiral wave concept of functional reentry in the atrium.
Athill et al. (Tue,) conducted a other in Functional reentry in the atrium (n=13). Transmembrane potential near the core of functional reentry vs. Transmembrane potential in the periphery was evaluated on Transmembrane potential amplitude (mV) (p=<0.001). In isolated canine right atria, cells near the core of functional reentry had significantly reduced transmembrane potential amplitude, duration, and (dV/dt)max compared to cells in the periphery (P<0.001).